in reality you pick the best person for the job, based upon their whole experience and education background
This is a pretty important factor. There is simply no way that a pilot can hold the skills to fly everything well. It is a stretch to think that a pilot can even safely fly everything - the scope of aircraft and operations is just too broad.
It'll be better to focus on at least a range of aircraft types, and operations, if not a class of aircraft. That's not to say that you won't be able to grow those skills laterally.